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Reserve, Utah, was completed, in connection with which 6 subdivision plats were made.

The drafting of about 50 per cent of the plat of the exterior boundary of the Yosemite National Park, California, which is also part of the boundaries of the Sierra and Stanislaus forest reserves, was completed, in connection with which 2 subdivision plats were made.

Triplicate copies of about 500 pages of forest reserve boundary notes were typewritten.

TRIANGULATION AND COMPUTING SECTION.

FIELD WORK.

EASTERN DIVISION.

Primary triangulation, primary traverse, and precise leveling were carried on at various times by seven parties. This work was distributed over portions of 18 States-Alabama, Arkansas, Iowa, Indiana, Kentucky, Louisiana, Maine, Missouri, Illinois, Michigan, Nebraska, North Carolina, Ohio, Pennsylvania, South Carolina, Virginia, West Virginia, and Wisconsin. The total area covered by this primary control was 19,130 square miles, of which 17,315 square miles were controlled by primary traverse. The result of this control was to make available seventy-four 15-minute quadrangles and three 30-minute quadrangles in which to prosecute future topographic surveys. In the progress of this work 38 triangulation stations were permanently marked and their geodetic positions determined, and 3,261 miles of primary traverse were run.

Alabama.-Additional control for the Opelika 30-minute quadrangle, in Chambers and Lee counties, was obtained by 78 miles of primary traverse.

Arkansas.-The Fort Smith 30-minute quadrangle, covering portions of the counties of Crawford and Sebastian, was controlled by 141 miles of primary traverse, so distributed as to furnish control for four 15-minute quadrangles, into which the original 30-minute quadrangle will be subdivided.

Georgia.-The Talbotton 30-minute quadrangle, in Harris, Meriwether, Muscogee, and Talbot counties, was controlled by 122 miles of primary traverse. The Dahlonega special quadrangle, in Lumpkin County, was controlled by 48 miles of primary traverse.

Illinois. Control for the Belleville, Breeze, Mahomet, Springfield, Tallula, Urbana, and Wheaton quadrangles, in the counties of Champaign, Clinton, Dupage, Madison, Menard, and Sangamon, was secured by 403 miles of primary traverse. A line of precise levels, 87 miles in length, was run in the fall of 1905 from Pekin along the Peoria and Eastern Railway to Champaign.

Indiana.-Portions of the New Albany, Prospect, and River View quadrangles, in the counties of Clark, Floyd, and Harrison, were controlled by 97 miles of primary traverse.

Iowa-Nebraska.-The Nebraska City quadrangle, covering portions of Fremont County, Iowa, and Otoe County, Nebr., was controlled by 68 miles of primary traverse, of which 50 miles are in Nebraska and 18 miles in Iowa. A line of precise levels, 142 miles in length, was run from Council Bluffs to Des Moines, Iowa.

Kentucky-In Bullitt, Jefferson, Shelby, and Spencer counties 76 miles of primary traverse were run for the control of the Shelbyville and Taylorsville quadrangles.

Louisiana. The Baton Rouge, Grossetete, and Whitecastle quadrangles, covering portions of Ascension, Berryville, and East Baton Rouge parishes, were controlled by 134 miles of primary traverse.

Maine. The Lewiston and Poland quadrangles, in Androscoggin and Oxford counties, were controlled by means of 6 occupied and 8 intersected triangulation stations.

Michigan.-The Howell, Leonard, Milford, Pontiac, and Rochester quadrangles, in Lapeer, Livingston, and Oakland counties, were controlled by 201 miles of primary traverse.

Mississippi.-The Jackson, Florence, Raymond, and Terry 15-minute quadrangles, in Copiah, Hinds, Madison, and Rankin counties, were controlled by 149 miles of primary traverse.

Missouri. The Atlanta, Macon, Shelbyville, and Shelbina quadrangles, in Macon, Monroe, and Randolph counties, were controlled by 137 miles of primary traverse.

North Carolina.-The Beckford, Winton, Four Oaks, Salemburg, Charlotte, and Matthews 15-minute quadrangles, in the counties of Bertie, Cabarrus, Gates, Hertford, Mecklenburg, Pasquotank, Johnston, and Sampson, were controlled by 410 miles of primary traverse. During the season of 1905 two lines of precise levels were run; the first from Durham along the Southern Railway northward to the Virginia State line, a distance of 50 miles; the second from Greensboro along the Southern Railway to Madison, thence along the Norfolk and Western Railway to the Virginia State line near Price, a distance of 42 miles.

In

Ohio.-Primary-traverse control was carried on in two areas. the northwestern portion of the State, in the counties of Defiance, Fulton, Henry, Williams, Lucas, and Wood, nine quadrangles were controlled by 289 miles of primary traverse; and in the central portion of the State, in the counties of Coshocton, Fairfield, Licking, Muskingum, and Perry, eight quadrangles were controlled by 369 miles of traverse. A line of precise levels was run along the Norfolk and Western Railway from Chillicothe to Columbus, a distance of 52 miles.

Pennsylvania.-In Warren County two 15-minute quadrangles were controlled by locating 10 triangulation stations. In Berks, Lancaster, and York counties three quadrangles were controlled by 179 miles of primary traverse.

South Carolina.-The Sharon and Rockhill quadrangles, in the counties of Chester and York, were controlled by 139 miles of primary traverse.

Virginia. The lines of precise levels previously mentioned under the heading of North Carolina were extended into Virginia--the first line to Clarksville, a distance of 6 miles, and the second line from Price to Buchanan, a distance of 100 miles.

West Virginia.-A reconnaissance triangulation was extended over the Horton and Elkins quadrangles, in Randolph and Tucker counties; signals were erected on 9 stations, and observations completed at 4 of them.

Wisconsin.-The La Crosse and Sparta quadrangles, in Monroe County, were controlled by 8 triangulation stations. The Cross Plains, Clyman, Delavan, Hartford, Janesville, Shopiere, Port Washington, Waukesha, and West Bend quadrangles, in Dodge, Iowa, Madison, Monroe, Milwaukee, Ozaukee, Rock, Walworth, and Washington counties, were controlled by 221 miles of primary traverse.

WESTERN DIVISION.

Triangulation was carried on at various times during the year by eleven parties and primary traverse by one party. This work was distributed over portions of eight States and Territories-California, Montana, New Mexico, Oklahoma, Oregon, Utah, Washington, and Wyoming. The total area covered by this primary control was 32,300 square miles, of which 400 square miles were controlled by primary traverse. The result of this control was to make available five 15-minute quadrangles, twenty-four 30-minute quadrangles, and seven special maps in which to prosecute future surveys. In the progress of this work 290 new triangulation stations were selected, permanently marked, and their geodetic positions determined, and 63 miles of primary traverse were run.

California.-Four 15-minute quadrangles, in the counties of Colusa, Sacramento, and Yolo, were controlled by 63 miles of primary traverse, and the Yosemite Special quadrangle, in Mariposa County, was controlled by locating 10 triangulation stations.

Montana.-Portions of three quadrangles, in Fergus County, were controlled by occupying 9 triangulation stations and locating 12 points by intersections.

Nevada-California.-Control for the Amargosa Special map, covering an area of 7,000 square miles in Inyo County, Cal., and Esmeralda and Nye counties, Nev., was secured by two triangulation parties; 18 stations were occupied and 7 points were located by intersections. Oklahoma.-Five quadrangles, in Lincoln, Logan, Pawnee, and Payne counties, were controlled by one triangulation party, which occupied 20 new stations and located 20 points by intersections.

Utah.—An area of 1,000 square miles, including the Iron Springs Special quadrangle, in Beaver and Iron counties, was controlled by the location of 7 triangulation stations.

Washington. Triangulation control for portions of four quadrangles, in Skagit and Whatcom counties, was secured by one party, which occupied 17 new stations and located 15 additional points by intersections.

TRIANGULATION OF FOREST RESERVES.

California, Sierra Reserve.—Triangulation control for this reserve was completed by the occupation of 17 primary stations and the location by intersection of 16 secondary points by one party. Another party located 5 triangulation stations for the control of the Bridgeport quadrangle, in Mono County.

California, Trinity Reserve.-Four 30-minute quadrangles, in Del Norte and Siskiyou counties, were controlled by 15 triangulation stations.

Idaho, Priest River Reserve.—Triangulation control for an area of 800 square miles in Kootenai County was partly completed by the occupation of 3 old and 2 new stations.

Montana, Hellgate Reserve.-An area of 1,200 square miles in Granite and Ravalli counties was controlled by occupying 9 new stations and locating 25 points by intersections.

New Mexico, proposed reserves.-One 30-minute quadrangle in Rio Arriba County was partly controlled by one party, which occupied 10 triangulation stations and located several points by intersections. An area of 1,000 square miles in Socorro County was triangulated by another party, which occupied 5 new stations and located 6 points by intersections.

Wyoming, Yellowstone Reserve.—An area of 4,500 square miles in Bighorn, Fremont, and Natrona counties was controlled by one triangulation party, which selected, occupied, and monumented 25 new stations and located 13 secondary points.

OFFICE WORK.

The office computation of triangulation, primary traverse, and adjustment of level circuits was carried on in this section as heretofore. The results of primary triangulation and primary traverse in 26 States were summarized and published in Bulletin No. 276.

The results for spirit leveling in the State of New York for the years 1896-1905, inclusive, were published in Bulletin No. 281; and the results of leveling in Pennsylvania for the years 1899-1905, inclusive, were published in Bulletin No. 288. The triangulation and leveling plats of all States were brought up to date, as well as the card catalog of triangulation and primary traverse stations. The preparation of triangulation and leveling data for chiefs of field parties and in reply to requests of persons not connected with the Survey required the time of a considerable portion of the office force.

During the year the following results were computed:

EASTERN DIVISION.

Alabama. For the control of the Opelika 30-minute quadrangle, in Chambers and Lee counties, 623 latitudes and departures and 58 geographic positions were computed. Level circuits in the Birmingham and Leeds quadrangles, in Jefferson County, were adjusted.

Arkansas. In the Fort Smith quadrangle, in Crawford and Sebastian counties, 691 latitudes and departures and 117 geographic positions were computed. Level circuits in the Harrison quadrangle, in Boone and Carroll counties, were adjusted.

Delaware. The results of leveling in Kent, Newcastle, and Sussex counties were revised and rearranged.

Georgia. For the Dahlonega quadrangle, in Lumpkin County, 831 latitudes and departures and 40 geographic positions were computed. In the Talbotton quadrangle, in Harris, Meriwether, Muscogee, and Talbot counties, 993 latitudes and departures and 99 geographic positions were computed. Level circuits in the Griffin and Talbotton quadrangles were also adjusted.

Illinois. For the Springfield, Tallula, Urbana, Mahomet, Belleville, Breese, and Wheaton quadrangles, in Champaign, Clinton, Dupage, Madison, Menard, and Sangamon counties, 1,411 latitudes and departures and 336 geographic positions were computed. Level circuits in the Breese, Belleville, Eldorado, Mahomet, New Haven, Springfield, and Urbana quadrangles, in Champaign, Clinton, Gallatin, Madison, Menard, Sangamon, Saline, and White counties, were adjusted, and the office computation of the precise line from Pekin to Champaign was made.

Indiana. For the New Albany, Prospect, and River View quadrangles, in Clark, Floyd, and Harrison counties, 758 latitudes and departures and 80 geographic positions were computed.

Iowa.-Level circuits in the Des Moines quadrangle, in Polk County, were adjusted, and office computation of the precise line from Council Bluffs to Des Moines was completed. For the portion of the Nebraska City quadrangle lying within Fremont County, Iowa, 60 latitudes and departures and 10 geographic positions were computed.

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